es of orderings (an abstract version of real spectras of formally real fields), for which they are expressed as local-global principles: A property of quadratic forms (expressed as...
Abstract Formal topology is today an established topic in the development of constructive mathematics and constructive proofs for many classical results of general topology have be...
We examine the Dual Ramsey Theorem and two related combinatorial principles VW(k, l) and OVW(k, l) from the perspectives of reverse mathematics and effective mathematics. We give a...
Under certain cardinal arithmetic assumptions, we prove that for every large enough regular cardinal, for many regular < , many stationary subsets of concentrating on cofinali...
A method is described for obtaining conjunctive normal forms for logics using Gentzen-style rules possessing a special kind of strong invertibility. This method is then applied to ...